Conversion of cellulose into 5-hydroxymethylfurfural in an H2O/tetrahydrofuran/cyclohexane biphasic system with Al2(SO4)3 as the catalyst

Abstract

aqueous phase under the reaction temperature, jointly leading to high V org /V aque , high C[Al 2 (SO 4 ) 3 ] aque and low C[Al 2 (SO 4 ) 3 ] org in the biphasic system. All of these results yield the excellent performance of these biphasic systems in the conversion of cellulose into HMF. The addition of CHX into the biphasic system can decrease the solubility of Al 2 (SO 4 ) 3 in the organic phase, thus improving the stability of HMF in the reaction system. The influences of catalyst usage, reaction temperature and time, and cellulose/ solvent ratio were all explored, and a high HMF yield of 71.2% was obtained in the H 2 O-THF-CHX biphasic system with an H 2 O/THF/CHX volume ratio of 3/16/3 under optimized conditions.

A Review on Green and Efficient Synthesis of 5-Hydroxymethylfurfural (HMF) and 2,5-Furandicarboxylic Acid (FDCA) from Sustainable Biomass

“…42 An excess amount of organic phase can bring about positive effects in the synthesis of HMF. Shi et al 43 maintained the use of a high organic phase/aqueous phase ratio. However, the catalyst was not allowed to move into the organic phase.…”

“…CHX helped lower the solubility of the catalyst in the organic phase, keeping HMF stable. 43 Another factor that can affect the performance of biphasic catalysts in the synthesis of HMF is the substrate/ solvent ratio. For example, the cellulose/solvent ratio increase was reported to decrease the HMF yield, with maximum HMF yield at a ratio of 1/22.…”

“…For example, the cellulose/solvent ratio increase was reported to decrease the HMF yield, with maximum HMF yield at a ratio of 1/22. 43 The higher the partition coefficient of the extracting solvent, the better the HMF yield and highly efficient synthesis. Blumenthal et al 45 used a thermodynamic model, COSMO-RS, to determine the best organic solvent for extracting HMF from aqueous phase.…”

“…In fact, the higher the organic phase/H 2 O ratio, the better the solvent system’s efficiency and higher the HMF yield. Shi et al . also reported that the V org / V aqs ratio was very high (50), ensuring high extraction of HMF into the organic phase.…”

Solvent Effects Enable Efficient Tandem Conversion of Cellulose and Its Monosaccharides Towards 5‐Hydroxymethylfurfural

“…[96] Processes for the purification of the product HMF include evaporation concentration, column chromatography purification (separation according to the different partition coefficients of the components in the reaction solution), and sodium hydroxide neutralization, among others. Biphasic solvents were widely used in the preparation of HMF in recent studies, [97] in which the H 2 O was often used as the reaction phase, and the product obtained after the completion of the reaction in H 2 O could be rapidly extracted into the organic phase as the extraction phase, [98] as shown in Figure 9. [99] The advantages are the reduction of residence time of HMF in the reaction phase, the improvement of the partition coefficient R-value, [100] and the inhibition of HMF rehydration and condensation with carbohydrates.…”